To provide a photosensitive composition excellent in a patterning property and capable of producing an organic thin-film transistor exhibiting high carrier mobility by being used in an insulation layer. A photosensitive composition comprising a polymer compound containing at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2) and a compound having at least two azide groups: In the formula (1), Ar1 represents a phenyl group or a naphthyl group, and in the formula (2), Ar2 represents a phenyl group or a naphthyl group. l and m are numbers satisfying that 1≥15 and l+m>90 when the total amount of all repeating units contained in the above-described polymer compound is taken as 100.